Cochlear implantation has become a viable treatment for profound hearing loss in young, prelingually deafened children. This project will determine whether home-based rehabilitation will increase the benefits of cochlear implant usage. Rehabilitation will consist of computerized audiovisual speech training for the children and communication training for their parents. Children who are born without functional hearing or who acquire a complete hearing loss before the age of 18 months must learn to speak using only visual and proprioceptive information. Rarely do they develop intelligible speech. Simultaneous study of speech aerodynamics, acoustics and intelligibility will indicate whether prelingually deafened children who receive a multichannel cochlear implant develop more appropriate speech behaviors than those who do not, and whether age at implantation affects their potential to benefit. In addition, these data and data from studies of delayed auditory feedback, device on/off, and sidetone attenuation experiments will shed light on the role of audition in developing and regulating speech production.